Thermal bridging through structural framing members can be a major source of conductive heat losses through a building envelope. The need for improved thermal performance in buildings has led to the increase in popularity of two techniques for enhancing building thermal insulation. According to a first method, a wall conventionally framed with 2.times.4 studs or other dimensional lumber is covered, either on the inside or outside surfaces with continuous rigid insulation board sheathing. A major limitation of this technique is the relatively high economic and environmental cost of the rigid insulation boards. Perhaps more significantly, certain problems exist with the structural properties of this type of construction assembly. For example, using a continuous layer of foam sheathing on exterior portions of the framing generally requires the use of cross-bracing to impart resistance to wall racking and wind loading. Alternatively, using rigid insulation sheathing on interior wall surfaces typically results in reduced areas of structural surfaces for attaching interior wall coverings such as wallboard in corners. Increased length mechanical fasteners such as screws or nails are also required for hanging wallboard or mounting pictures, shelving, etc. Such walls may also exhibit poor resistance to compressive loading that can be manifest in wavy, non-true walls with screw or nail heads popping out of the wallboard.
According to the other method for enhancing building thermal insulation, dimensional lumber which is deeper than necessary to support anticipated structural loads may be used to conventionally frame the walls, such as 2.times.6 studs instead of 2.times.4 studs. Use of deeper studs results in thicker walls with deeper cavities which can accommodate more cavity insulation.